Miniaturized 3-D Solenoid-Type Micro-Heaters in Coordination With 3-D Microfluidics

We fabricate and characterize a prototype on-chip 3-D micro-heater inside a fused silica chip, which is coordinated with a microfluidic channel. By means of enhanced femtosecond laser wet etching followed by a micro-mold injection process of a liquid metal, the solenoid-type metallic micro-heater, with a size of π × 100
²
× 1120 μm
³
, was fabricated twining outward a linear microfluidic channel. The micro-heater exhibits excellent performances, such as precisely current-temperature controllability (temperature range from 0°C to 130°C), rapid heating/cooling process (up to 16 °C/s at the beginning of the heating process and 15.8 °C/s at the beginning of cooling process), and uniform temperature distribution. This work not only provides a high-quality micro-heater for biological or chemical applications, which requires rigid temperature control capabilities, but also proposes a practical route to the fabrication of comprehensive truly-3-D lab-on-a-chip devices and microelectromechanical systems.